Four-sided picture frame



FIG. 1 is a perspective view of the four-sided picture frame;

FIG. 2 is a top view of the frame of FIG. 1, the bottom view being the same; and,

FIG. 3 is a front view of the frame of FIG. 1, the left side view, right side view and back side view all being the same.

The picture frame is shown with a symbolic break in its height, represented by jagged, broken lines. The appearance of any portion of the article between the jagged, broken lines forms no part of the claimed design. 

CLAIM The ornamental design for a four-sided picture frame, as shown and described. 